Questions tagged [vacuum]
The vacuum command in postgres releases unused space. Be sure to also include the [postgres] tag, and version tag such as [postgresql-9.6]. Include an operating system tag,
161
questions
63
votes
2
answers
68k
views
How to view the current settings of Autovacuum in Postgres?
I've found a million examples of how to set Autovacuum's configuration settings, but can't seem to find how to list the current configuration.
Postgres 9.1 is the version I'm most interested in.
- 1,115
49
votes
5
answers
53k
views
Aggressive Autovacuum on PostgreSQL
I'm trying to get PostgreSQL to aggressively auto vacuum my database. I've currently configured auto vacuum as follows:
autovacuum_vacuum_cost_delay = 0 #Turn off cost based vacuum
...
- 763
46
votes
6
answers
55k
views
I need to run VACUUM FULL with no available disk space
I have one table that is taking up close to 90% of hd space on our server. I have decided to drop a few columns to free up space. But I need to return the space to the OS. The problem, though, is ...
- 563
39
votes
3
answers
41k
views
Are regular VACUUM ANALYZE still recommended under 9.1?
I'm using PostgreSQL 9.1 on Ubuntu. Are scheduled VACUUM ANALYZE still recommended, or is autovacuum enough to take care of all needs?
If the answer is "it depends", then:
I have a largish database (...
- 1,423
36
votes
1
answer
52k
views
VACUUM returning disk space to operating system
VACUUM usually does not return disk space to operating system, except in some special cases.
From the docs:
The standard form of VACUUM removes dead row versions in tables and indexes and marks the ...
- 605
32
votes
4
answers
59k
views
How much time will a vacuum/autovacuum operation take?
I manage a big (some hundreds of gigs) database containing tables with various roles, some of them holding millions of records. Some tables only receive large number of inserts and deletes, some other ...
- 465
27
votes
3
answers
41k
views
VACUUM FREEZE vs. VACUUM FULL
Can someone explain the difference between these types of VACUUM in PostgreSQL?
I read the doc but it just says that FULL locks the tables and FREEZE "freezes" the tuples. I think that's the same. Am ...
- 373
21
votes
1
answer
13k
views
PostgeSQL 9.3: Is it safe to stop VACUUM FULL?
I'm using PostgreSQL 9.3 on RDS. Once in a while, I run a VACUUM FULL operation on the database. However, such operation can take quite a while and it blocks other tables, so the need to stop the ...
- 11.5k
21
votes
1
answer
32k
views
Does cancelling an (AUTO)VACUUM process in PostgreSQL make all the work done useless?
In some occasions, and after making a massive update, insert or delete from a table, I have started a VACUUM FULL ANALYZE to make sure the DB was not getting too bloated. Doing it in a production ...
- 13.3k
20
votes
4
answers
36k
views
Should I manually VACUUM my PostgreSQL database if autovacuum is turned on?
I use software which makes a big PostgreSQL database (there is a table with a million rows in it) and the developers says I should VACUUM and ANALYZE periodically. But the PostgreSQL database default ...
- 325
19
votes
1
answer
4k
views
Is it worth it to run VACUUM on a table that only receives INSERTs?
In a 2015 re:Invent talk, AWS mentioned that vacuum should be run not only after updates or deletes but also after inserts. Here is the relevant part of the talk:
http://www.youtube.com/watch?v=...
- 621
18
votes
2
answers
14k
views
PostgreSQL difference between VACUUM FULL and CLUSTER
I have a table with 200 GB of size occupied by data and 180 GB of size by the 6 indexes on it. It is 30% bloated, so I want to reclaim unwanted space occupied by it. It is clustered on job_id_idx ...
- 181
13
votes
1
answer
7k
views
Does VACUUM FULL need ANALYZE
I'd be grateful for some insight into the VACUUM functionality within PostgreSQL 9.3. I read through the documentation and searched around a bit but could not find a definitive answer to this.
I'm ...
- 133
13
votes
1
answer
762
views
Disk file effects of delete and vacuum
I have a very frequently updated table with 240 million rows (and growing). Every three hours 1.5 million rows are inserted and 1.5 million are deleted. When I moved the cluster to a SSD this bulk ...
- 1,135
12
votes
3
answers
10k
views
Is it necessary to ANALYZE a table after an index has been created?
In my transaction, I am creating a temporary table:
create temporary table x on commit drop as
select ...
I also add an index on that table:
create index on x(some_column);
Is it now necessary to ...
- 123
12
votes
1
answer
3k
views
Busy table is not getting vacuumed
We're using Postgres 9.2 on Windows to store low-frequency timeseries data: we're inserting around 2000 rows per second every second 24 hours, 7 days a week with no downtime. There is a DELETE that ...
- 223
11
votes
4
answers
14k
views
VACUUM VERBOSE outputs, nonremovable "dead row versions cannot be removed yet"?
I have a Postgres 9.2 DB where a certain table has lots of nonremovable dead rows:
# SELECT * FROM public.pgstattuple('mytable');
table_len | tuple_count | tuple_len | tuple_percent | ...
- 211
11
votes
2
answers
15k
views
Why wouldn't VACUUM ANALYZE clear all dead tuples?
We run a "manual" VACUUM ANALYZE VERBOSE on some of our larger tables after we do major DELETE/INSERT changes to them. This seems to work without issue although sometimes a table's VACUUM job will run ...
- 213
11
votes
2
answers
2k
views
What fillfactor for caching table?
I have heavily updated / accessed table where I store serialized java objects. They are in the table for 2-3 hours (also are being updated during that period) and then removed. Size of table is around ...
- 163
11
votes
1
answer
1k
views
UPDATE on big table in PostgreSQL randomly takes too long
I'm trying to figure out why an UPDATE statement takes too long (>30 sec).
This is random, i.e. in most cases it finishes in under 100msec. However, sometimes (randomly) it takes > 30sec to ...
- 135
10
votes
1
answer
5k
views
Reclaim disk space from dropped column without downtime
I have a heavily used table (with around 5 million rows) in a PostgreSQL database in which I want to drop a column and reclaim the space the column used.
The docs suggest doing a table rewriting ...
- 479
10
votes
1
answer
2k
views
How to reclaim space taken by an index that partially built and was terminated by a power outage
I'm running postgres (postgis) 9.4.2 on a mac (10.10.4).
I've got a couple big tables (several TBs).
During an index build on one of them that takes about a week, I watched the available HD space ...
- 115
9
votes
2
answers
1k
views
Does SELECT remove dead rows like VACUUM does?
I was fiddling with VACUUM and noticed some unexpected behavior where SELECTing rows from a table seems to reduce the work VACUUM has to do afterwards.
Test Data
Note: autovacuum is disabled
CREATE ...
- 193
7
votes
1
answer
4k
views
What performance advantages does append-only postgres allow?
Suppose we have a Postgres Database with only a single table. It is known that no UPDATE statements will ever be run on it, nor will any DELETEs. It is 100% append-only.
Some databases exist that rely ...
- 173
6
votes
1
answer
23k
views
Postgres strategy for UPDATE SET x = NULL
It is not clear the strategy Postgres takes when columns are set to NULL:
UPDATE tbl SET
col1 = NULL,
col2 = NULL
WHERE created < current_date - INTERVAL '1 year';
Documentation https://www....
- 499
6
votes
1
answer
2k
views
Does UPDATE write a new row version for unchanged, TOASTed values?
I am working with a PostgreSQL table with a large TEXT field, which is theoretically updated on a regular basis. I have thought about storing the data directly in the filesystem, but with TOAST, the ...
- 183
6
votes
1
answer
2k
views
Is vacuuming a PostgreSQL materialized view necessary?
I understand it makes sense to analyze a Materialized View (MV), but since MVs are not updateable, does that imply that we need not ever vacuum a MV?
- 96
6
votes
1
answer
4k
views
PostgreSQL strategies to deal with disk filling up
I'm using PostgreSQL (8.4) to store data produced by an application making frequent inserts (in the table structure described below).
The database keeps growing with time and, since the newer data is ...
- 1,525
6
votes
1
answer
9k
views
Is VACUUM FULL necessary on a DROP TABLE / TRUNCATE approach for a datawarehouse
We are updating a datawarehouse on a weekly basis using a series of
TRUNCATE source_table1
COPY source_table1 FROM [...]
... for data import
and:
DROP TABLE IF EXISTS my_table
CREATE TABLE ...
- 213
5
votes
2
answers
3k
views
PostgreSQL unexplained table bloat
I have a table in a Postgres 8.2.15 database. The table bloated to almost 25GB but after running vacuum full and cluster the table size was dramatically smaller, well under 1GB. A few weeks later ...
- 121
5
votes
1
answer
1k
views
How to predict how much space a VACUUM FULL would reclaim?
Is there a way to determine in advance how much disk space a VACUUM FULL on a particular table would return to the OS? Therefore you can decide whether it's worth the cost in doing so.
Bonus if there'...
- 296
5
votes
1
answer
1k
views
For alignment optimized table is bigger than original table - why?
In another question I learned that I should optimize the layout from one of my tables to save space and have better performance. I did this, but ended up with a larger table than before and ...
- 927
5
votes
3
answers
4k
views
How to reclaim disk space after delete without rebuilding table?
Our PostgreSQL 9.0 Windows production server is running low on space.
In our 100GB database, we have a large table containing TOASTed binary data. We have deleted some rows and need to return the ...
- 281
5
votes
2
answers
3k
views
How to optimize a table for a very high-frequency updates?
I have a table that contains a list of tasks that need to be run periodically:
applaudience=> \d+ maintenance_task
Table "...
- 1,145
5
votes
1
answer
2k
views
PostgreSQL maintenance
I am new to PostgreSQL and want to know more about maintenance options in pgAdmin III.
I've read the documentation and now I know that vacuuming frees some space and I need to run it regularly. ...
- 151
4
votes
1
answer
8k
views
When is Postgres autovacuum executed
I am using an older version of Postgres (8.4.20). I know that the autovacuum process is executed frequently to free disk space of queries that deleted or updated data in tables. I have a database ...
- 143
4
votes
1
answer
2k
views
Does postgres efficiently re-use space from deleted rows?
From the docs:
In PostgreSQL, an UPDATE or DELETE of a row does not immediately remove the old version of the row [...] But eventually, an outdated or deleted row version is no longer of interest ...
- 39.7k
4
votes
1
answer
5k
views
What are "nonremovable row versions"?
I did full vacuum on postgresql-9.4 database and I have a lot of tables with nonremovable row versions. I would like to know what are these or where I can read about them.
INFO: vacuuming "public....
- 141
4
votes
1
answer
4k
views
Dropping indexes doesn't seem to release space to the OS. Can it?
I'm running PostgreSQL 9.1. I have noticed really alarmingly bad indexes are taking up a lot of space on my server, e.g:
evlampts=# SELECT
pg_size_pretty(pg_relation_size('mcdata_2011_07')) AS ...
- 824
4
votes
2
answers
6k
views
How to `vacuumlo` an RDS PostgreSQL database?
As you may have noticed, as a fully managed data base as a service product, AWS Relational Data base Service (RDS) restricts the execution of userland commands.
I was staging a production database, ...
- 66
4
votes
1
answer
7k
views
Postgres Vacuum in Function
After googleing a bit, it's plainly clear you cannot run vacuum from a function:
Postgres mailing - Vacuum behaviour in plpgsql function
You can't run VACUUM from inside a function because of ...
- 143
4
votes
1
answer
7k
views
VACUUM FULL fails with 'ERROR: Check free disk space'
I am using Postgres 9.4. I have a database that \l+ tells me is 164 GB. When I try to run VACUUM FULL on the database, I get this error (after many hours):
ERROR: could not extend file "base/18222/...
- 333
4
votes
1
answer
467
views
How do databases deal with file system fragmentation?
Especially analytic databases that try to optimize for queries that scan large portions of tables instead of randomly accessing specific rows. For example Redshift has a concept of a sort key that, ...
- 621
3
votes
1
answer
7k
views
Postgres VACUUM taking forever
I have an specific table that is taking forever o VACUUM.
There are no locks in the DB and even letting it overnight the VACUUM didn't finish.
According to the statistics (ANALYZE works fine) the ...
- 187
3
votes
2
answers
1k
views
pg_relation_size does not show any difference after VACUUM ANALYZE
I wrote a script to backup a postgresql using COPY and then delete those records. I have used pg_relation_size before and after delete.
pg_relation_size
DELETE
VACUUM ANALYZE
pg_relation_size
But ...
- 2,201
3
votes
3
answers
3k
views
Is it possible to never run vacuum full in PostgreSQL
Since a VACUUM FULL locks tables, it is unacceptable for us in our production environment.
Is it possible to only run VACUUM and never VACUUM FULL on a production system?
Does VACUUM make space ...
- 755
3
votes
3
answers
1k
views
Reclaim space after a failed VACUUM FULL
I made small miscalculation and my VACUUM FULL ended up filling the disks of the instance. I managed to free enough space to restart postgres but I am afraid it won't be enough to run VACUUM FULL to ...
- 209
3
votes
1
answer
5k
views
uncommitted xmin during vacuum, what to do?
Running vacuum on two specific tables in my postgresql 10 database results in the following error:
VACUUM (FULL|ANALYZE|FREEZE|) table;
ERROR: uncommitted xmin 359569171 from before xid cutoff ...
- 881
3
votes
1
answer
948
views
Are autovacuum VACUUMs slower than a manual VACUUM?
I have a few large tables that take days to autovacuum, sometimes resulting in poor performance until the vacuum finishes. Most of the recommendations I've seen mention doing a manual VACUUM during ...
- 177
3
votes
2
answers
5k
views
Vacuum vs Auto Vacuum
I am trying to find answers for my below few queries which will help me in fine tuning my postgres DB. I did some googling but was not able to find answer.
1) Out of vacuum or Auto vacuum which is ...
- 43